Numerical modeling of conjugate heat and mass transfer with water vaporization in solid materials inside a convective hot air tunnel

Abstract

A two-dimensional conjugate model describes heat and mass transfer with liquid to vapor phase change of water in solid materials inside a hot air tunnel. Computational modeling allows to assess the evolution of convective fluid mechanics and heat convection in laminar airflow and coupled heat-mass transfer diffusion inside a rectangular solid. A transient finite volume method conjugate model characterizes the fluid mechanics and heat transfer in airflow, and the local convective heat (h(L)) and mass(hm(L)) transfer coefficients. The results indicate that h(L) was found to vary spatially on each surface of the solid between 5.71 and 101.62 W/m2K, while hm(L) varied from 5.05×10−6 to 1.38×10−6 m/s. Heat and mass transfer by unsteady diffusion inside the solid were accounted for by a second transient diffusion model. Experimental findings of apple slice dehydration kinetic reported in the literature allowed to validate the coupled heat and mass transfer model, with deviation lower than 2% for the water mass losses. Finally, the proposed model applied on a thin-layer of murta berry puree inside a hot air tunnel predicted transient non-uniform heat and mass transfer processes, with a difference of 13.5 K between the coldest and front areas.